Genes Conferring Copper Resistance inSinorhizobium melilotiCCNWSX0020 Also Promote the Growth ofMedicago lupulinain Copper-Contaminated Soil

ABSTRACTSinorhizobium melilotiCCNWSX0020, isolated from root nodules ofMedicago lupulinagrowing in gold mine tailings in the northwest of China, displayed both copper resistance and growth promotion of leguminous plants in copper-contaminated soil. Nevertheless, the genetic and biochemical mechanisms responsible for copper resistance inS. melilotiCCNWSX0020 remained uncharacterized. To investigate genes involved in copper resistance, anS. melilotiCCNWSX0020 Tn5insertion library of 14,000 mutants was created. Five copper-sensitive mutants, named SXa-1, SXa-2, SXc-1, SXc-2, and SXn, were isolated, and the disrupted regions involved were identified by inverse PCR and subsequent sequencing. Both SXa-1 and SXa-2 carried a transposon insertion inlpxXL(SM0020_18047), encoding the LpxXL C-28 acyltransferase; SXc-1 and SXc-2 carried a transposon insertion inmerR(SM0020_29390), encoding the regulatory activator; SXn contained a transposon insertion inomp(SM0020_18792), encoding a hypothetical outer membrane protein. The results of reverse transcriptase PCR (RT-PCR) combined with transposon gene disruptions revealed thatSM0020_05862, encoding an unusual P-type ATPase, was regulated by the MerR protein. Analysis of the genome sequence showed that this P-type ATPase did not contain an N-terminal metal-binding domain or a CPC motif but rather TPCP compared with CopA fromEscherichia coli. Pot experiments were carried out to determine whether growth and copper accumulation of the host plantM. lupulinawere affected in the presence of the wild type or the different mutants. Soil samples were subjected to three levels of copper contamination, namely, the uncontaminated control and 47.36 and 142.08 mg/kg, and three replicates were conducted for each treatment. The results showed that the wild-typeS. melilotiCCNWSX0020 enabled the host plant to grow better and accumulate copper ions. The plant dry weight and copper content ofM. lupulinainoculated with the 5 copper-sensitive mutants significantly decreased in the presence of CuSO4.

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Molecular insight into extreme copper resistance in the extremophilic archaeon ‘Ferroplasma acidarmanus’ Fer1

Microbiology ◽

10.1099/mic.0.28076-0 ◽

2005 ◽

Vol 151 (8) ◽

pp. 2637-2646 ◽

Cited By ~ 60

Author(s):

Craig Baker-Austin ◽

Mark Dopson ◽

Margaret Wexler ◽

R. Gary Sawers ◽

Philip L. Bond

Keyword(s):

Metal Binding ◽

Stress Proteins ◽

Mine Drainage ◽

Copper Resistance ◽

Genes Encoding ◽

Ferroplasma Acidarmanus ◽

Copper Contaminated ◽

P Type ◽

Growth Experiments ◽

Insight Into

‘Ferroplasma acidarmanus’ strain Fer1 is an extremely acidophilic archaeon involved in the genesis of acid mine drainage, and was isolated from copper-contaminated mine solutions at Iron Mountain, CA, USA. Here, the initial proteomic and molecular investigation of Cu2+ resistance in this archaeon is presented. Analysis of Cu2+ toxicity via batch growth experiments and inhibition of oxygen uptake in the presence of ferrous iron demonstrated that Fer1 can grow and respire in the presence of 20 g Cu2+ l−1. The Fer1 copper resistance (cop) loci [originally detected by Ettema, T. J. G., Huynen, M. A., de Vos, W. M. & van der Oost, J. Trends Biochem Sci 28, 170–173 (2003)] include genes encoding a putative transcriptional regulator (copY), a putative metal-binding chaperone (copZ) and a putative copper-transporting P-type ATPase (copB). Transcription analyses demonstrated that copZ and copB are co-transcribed, and transcript levels were increased significantly in response to exposure to high levels of Cu2+, suggesting that the transport system is operating for copper efflux. Proteomic analysis of Fer1 cells exposed to Cu2+ revealed the induction of stress proteins associated with protein folding and DNA repair (including RadA, thermosome and DnaK homologues), suggesting that ‘Ferroplasma acidarmanus’ Fer1 uses multiple mechanisms for resistance to high levels of copper.

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Evaluation of the effect of microorganisms in Arachis pintoi roots on the potential of copper absorption in land

Science and Technology Development Journal ◽

10.32508/stdj.v18i4.934 ◽

2015 ◽

Vol 18 (4) ◽

pp. 138-152

Author(s):

Nga Diep Yen Dang ◽

Trong Thi Kim Pham

Keyword(s):

Contaminated Soil ◽

Low Cost ◽

Root Nodules ◽

The Other ◽

Contaminated Sites ◽

Copper Accumulation ◽

Arachis Pintoi ◽

Whole Plant ◽

Copper Contaminated ◽

Translocation Factors

The research was carried out to evaluate the potential phytoextraction and phytostability of perennial peanut (Arachis pintoi) and to determine the influence of the isolated microorganisms from the root nodules of Arachis pintoi on coppercontaminated soil to improve the ability of treatment metal in soil pollution. Perennial peanuts were planted in the experimental pots which had unsterilized and sterilized soil. Different quanlities of CuSO4.5H2O were directly homogenized into sieved soil to formulate mixtures containing Cu in concentrations (mg/kg) of 200, 400 and 600. In addition, sterilized soil was contaminated by adding Cu with 400 mg/kg. The other pots had copper- contaminated sterilized soil and was added the isolated microorganisms from the root nodules of Arachis pintoi. Our results showed that the perennial peanut had high phytomass production and grew normally in the soil with 200 mg/kg of Cu. The copper accumulation was determined of 668.2, 107 and 561.2 mg/kg in the whole plant, roots and shoots, respectively in plants which were cultivated in the soil with 200 mg/kg of Cu. In the soil with 400 mg/kg and 600 mg/kg of Cu, the plants showed low biomass production and the plants had been poisonous. Both bioconcentration factors (BCF) and translocation factors (TF) were used to estimate a plant’s potential for the purpose of phytoremediation. The highest BCF and TF for Cu concentrations were 3.341 and 5.24 with 200 mg/kg of Cu, respectively. Both factors were higher than 1 therefore Archis pintoi is a potential plant for copper phytoextraction in copper contaminated sites at the concentration of 200-400 mg/kg. The isolated microrganism from the root nodules of Arachis pintoi on copper- contaminated soil was Burkholderia kururiensi PR1, which was a species of proteobacteria and stimulated plant growth. However, the result showed that Burkholderia kururiensi is unable to resistant to concentration of copper (25 mg/L). More research on the other isolated microorganisms of the root system to enhance the Cu accumulation in plants should be carried. Finally, these results showed the potential of the heavy metal phytoextraction of the perennial peanut in contaminated soil. It is easy to apply because of the low cost.

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Effect of Temperature on Copper Accumulation of Brassica juncea Coss. and Zea mays L. Grown in Copper-Contaminated Soils

Environment Control in Biology ◽

10.2525/ecb1963.41.183 ◽

2003 ◽

Vol 41 (2) ◽

pp. 183-187

Author(s):

Hiromichi INOUE ◽

Kazutoshi SAEKI ◽

Jiro CHIKUSHI

Keyword(s):

Zea Mays ◽

Brassica Juncea ◽

Contaminated Soils ◽

Zea Mays L ◽

Effect Of Temperature ◽

Copper Accumulation ◽

Copper Contaminated

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FixJ family regulator AcfR of Azorhizobium caulinodans is involved in symbiosis with the host plant

BMC Microbiology ◽

10.1186/s12866-021-02138-w ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Wei Liu ◽

Xue Bai ◽

Yan Li ◽

Haikun Zhang ◽

Xiaoke Hu

Keyword(s):

Signal Transduction ◽

Host Plant ◽

Type Strain ◽

Wild Type Strain ◽

Response Regulator ◽

Azorhizobium Caulinodans ◽

Wild Type ◽

Response Regulators ◽

Free Living ◽

Two Component

Abstract Background A wide variety of bacterial adaptative responses to environmental conditions are mediated by signal transduction pathways. Two-component signal transduction systems are one of the predominant means used by bacteria to sense the signals of the host plant and adjust their interaction behaviour. A total of seven open reading frames have been identified as putative two-component response regulators in the gram-negative nitrogen-fixing bacteria Azorhizobium caulinodans ORS571. However, the biological functions of these response regulators in the symbiotic interactions between A. caulinodans ORS571 and the host plant Sesbania rostrata have not been elucidated to date. Results In this study, we identified and investigated a two-component response regulator, AcfR, with a phosphorylatable N-terminal REC (receiver) domain and a C-terminal HTH (helix-turn-helix) LuxR DNA-binding domain in A. caulinodans ORS571. Phylogenetic analysis showed that AcfR possessed close evolutionary relationships with NarL/FixJ family regulators. In addition, six histidine kinases containing HATPase_c and HisKA domains were predicted to interact with AcfR. Furthermore, the biological function of AcfR in free-living and symbiotic conditions was elucidated by comparing the wild-type strain and the ΔacfR mutant strain. In the free-living state, the cell motility behaviour and exopolysaccharide production of the ΔacfR mutant were significantly reduced compared to those of the wild-type strain. In the symbiotic state, the ΔacfR mutant showed a competitive nodule defect on the stems and roots of the host plant, suggesting that AcfR can provide A. caulinodans with an effective competitive ability for symbiotic nodulation. Conclusions Our results showed that AcfR, as a response regulator, regulates numerous phenotypes of A. caulinodans under the free-living conditions and in symbiosis with the host plant. The results of this study help to elucidate the involvement of a REC + HTH_LuxR two-component response regulator in the Rhizobium-host plant interaction.

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Toxicological effects, mechanisms, and implied toxicity thresholds in the roots of Vicia faba L. seedlings grown in copper-contaminated soil

Environmental Science and Pollution Research ◽

10.1007/s11356-015-5073-7 ◽

2015 ◽

Vol 22 (18) ◽

pp. 13858-13869 ◽

Cited By ~ 3

Author(s):

Xianghua Xu ◽

Zhicheng Huang ◽

Chengrun Wang ◽

Li Zhong ◽

Yuan Tian ◽

...

Keyword(s):

Vicia Faba ◽

Contaminated Soil ◽

Toxicological Effects ◽

Vicia Faba L ◽

Copper Contaminated

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OmpR and LeuO Positively Regulate the Salmonella enterica Serovar Typhi ompS2 Porin Gene

Journal of Bacteriology ◽

10.1128/jb.186.10.2909-2920.2004 ◽

2004 ◽

Vol 186 (10) ◽

pp. 2909-2920 ◽

Cited By ~ 39

Author(s):

Marcos Fernández-Mora ◽

José Luis Puente ◽

Edmundo Calva

Keyword(s):

Salmonella Enterica ◽

Type Strain ◽

Wild Type Strain ◽

Phosphorylation Site ◽

Regulatory Region ◽

Random Mutagenesis ◽

Fold Increase ◽

Upstream Regulatory Region ◽

Wild Type ◽

Transposon Insertion

ABSTRACT The Salmonella enterica serovar Typhi ompS2 gene codes for a 362-amino-acid outer membrane protein that contains motifs common to the porin superfamily. It is expressed at very low levels compared to the major OmpC and OmpF porins, as observed for S. enterica serovar Typhi OmpS1, Escherichia coli OmpN, and Klebsiella pneumoniae OmpK37 quiescent porins. A region of 316 bp, between nucleotides −413 and −97 upstream of the transcriptional start point, is involved in negative regulation, as its removal resulted in a 10-fold increase in ompS2 expression in an S. enterica serovar Typhi wild-type strain. This enhancement in expression was not observed in isogenic mutant strains, which had specific deletions of the regulatory ompB (ompR envZ) operon. Furthermore, ompS2 expression was substantially reduced in the presence of the OmpR D55A mutant, altered in the major phosphorylation site. Upon random mutagenesis, a mutant where the transposon had inserted into the upstream regulatory region of the gene coding for the LeuO regulator, showed an increased level of ompS2 expression. Augmented expression of ompS2 was also obtained upon addition of cloned leuO to the wild-type strain, but not in an ompR isogenic derivative, consistent with the notion that the transposon insertion had increased the cellular levels of LeuO and with the observed dependence on OmpR. Moreover, LeuO and OmpR bound in close proximity, but independently, to the 5′ upstream regulatory region. Thus, the OmpR and LeuO regulators positively regulate ompS2.

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AcrAB Multidrug Efflux Pump Is Associated with Reduced Levels of Susceptibility to Tigecycline (GAR-936) in Proteus mirabilis

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.47.2.665-669.2003 ◽

2003 ◽

Vol 47 (2) ◽

pp. 665-669 ◽

Cited By ~ 113

Author(s):

Melissa A. Visalli ◽

Ellen Murphy ◽

Steven J. Projan ◽

Patricia A. Bradford

Keyword(s):

Proteus Mirabilis ◽

Efflux Pump ◽

Wild Type ◽

Multidrug Efflux ◽

Multidrug Efflux Pump ◽

Transposon Insertion ◽

Spectrum Activity ◽

Insertion Mutants ◽

Broad Spectrum Activity ◽

Increased Susceptibility

ABSTRACT Tigecycline has good broad-spectrum activity against many gram-positive and gram-negative pathogens with the notable exception of the Proteeae. A study was performed to identify the mechanism responsible for the reduced susceptibility to tigecycline in Proteus mirabilis. Two independent transposon insertion mutants of P. mirabilis that had 16-fold-increased susceptibility to tigecycline were mapped to the acrB gene homolog of the Escherichia coli AcrRAB efflux system. Wild-type levels of decreased susceptibility to tigecycline were restored to the insertion mutants by complementation with a clone containing a PCR-derived fragment from the parental wild-type acrRAB efflux gene cluster. The AcrAB transport system appears to be associated with the intrinsic reduced susceptibility to tigecycline in P. mirabilis.

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Associations between varied susceptibilities of PfATP4 inhibitors and genotypes in Ugandan Plasmodium falciparum isolates

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00771-21 ◽

2021 ◽

Author(s):

Oriana Kreutzfeld ◽

Stephanie A. Rasmussen ◽

Aarti A. Ramanathan ◽

Patrick K. Tumwebaze ◽

Oswald Byaruhanga ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Single Nucleotide Polymorphisms ◽

Ex Vivo ◽

Nucleotide Polymorphisms ◽

Wild Type ◽

Single Nucleotide ◽

Field Isolates ◽

Frequent Mutations ◽

Mixed Field ◽

P Type

Among novel compounds under recent investigation as potential new antimalarial drugs are three independently developed inhibitors of the Plasmodium falciparum P-type ATPase (PfATP4): KAE609 (cipargamin), PA92, and SJ733. We assessed ex vivo susceptibilities to these compounds of 374 fresh P. falciparum isolates collected in Tororo and Busia districts, Uganda from 2016-2019. Median IC 50 s were 65 nM for SJ733, 9.1 nM for PA92, and 0.5 nM for KAE609. Sequencing of pfatp4 for 218 of these isolates demonstrated many non-synonymous single nucleotide polymorphisms; the most frequent mutations were G1128R (69% of isolates mixed or mutant), Q1081K/R (68%), G223S (25%), N1045K (16%) and D1116G/N/Y (16%). The G223S mutation was associated with decreased susceptibility to SJ733, PA92 and KAE609. The D1116G/N/Y mutations were associated with decreased susceptibility to SJ733, and the presence of mutations at both codons 223 and 1116 was associated with decreased susceptibility to PA92 and SJ733. In all of these cases, absolute differences in susceptibilities of wild type (WT) and mutant parasites were modest. Analysis of clones separated from mixed field isolates consistently identified mutant clones as less susceptible than WT. Analysis of isolates from other sites demonstrated presence of the G223S and D1116G/N/Y mutations across Uganda. Our results indicate that malaria parasites circulating in Uganda have a number of polymorphisms in PfATP4 and that modestly decreased susceptibility to PfATP4 inhibitors is associated with some mutations now present in Ugandan parasites.

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